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digraph
Directed graph in adjacency list format.
Documentation
The digraph library is an implementation of a directed graph, where the edges are stored as adjacency lists indexed by node number.
The present version implements a yasos object that provides a number of methods for graph operations.
Directed graph procedures
The digraph object is created by procedure make-digraph:
[procedure] make-digraph:: NAME INFO [NODE-LIST [SUCC-LIST [PRED-LIST]]] -> SELECTORwhere:
- NAME is the graph name (string or symbol)
- INFO is an optional metadata object of an arbitrary type or #f
- NODE-LIST is an optional list of nodes to be inserted in the graph; each element of the list must be of the form (N INFO) where N is a unique node number (integer), and INFO is an optional metadata object describing the node.
- SUCC-LIST and PRED-LIST can be used to define the graph edges upon graph creation. If supplied, these arguments must be lists in which every element is of the form (I J INFO), where I and J are node numbers, and INFO is an optional metadata object.
The returned yasos object can take one of the following messages:
- name
- returns the graph name (string or symbol)
- info
- returns the graph metadata (arbitrary type)
- new-id!
- returns a procedure with no arguments, which returns the lowest available node number
- add-node!
- returns a procedure LAMBDA N INFO which inserts in the graph node with number N and metadata INFO; if the node already exists in the graph, it will be overwritten with the new metadata
- add-edge!
- returns a procedure LAMBDA EDGE which inserts in the graph the specifed edge; the edge is given by a list of the form (I J INFO), where I and J are source and destination nodes, respectively, and INFO is edge metadata of arbitrary type
- remove-node!
- returns a procedure LAMBDA N which removes node N and all its edges from the graph
- nodes
- returns a procedure with no arguments, which returns a list with the nodes of the graph and their metadata
- edges
- returns a procedure with no arguments, which returns a list with the edges of the graph and their metadata
- roots
- returns a procedure with no arguments, which returns a list with all nodes in the graph that do not have an predecessor
- terminals
- returns a procedure with no arguments, which returns a list with all nodes in the graph that do not have a successor
- order
- returns a procedure with no arguments, which returns the number of nodes in the graph
- size
- returns a procedure with no arguments, which returns the number of edges in the graph
- capacity
- returns a procedure with no arguments, which returns the size of the underlying dynamic vector
- succ
- returns a procedure LAMBDA N which returns a list with the successor nodes of node N
- pred
- returns a procedure LAMBDA N which returns a list with the predecessor nodes of node N
- succ-list
- returns a procedure with no arguments which returns a list containing the successor nodes for each node.
- pred-list
- returns a procedure with no arguments which returns a list containing the predecessor nodes for each node.
- out-edges
- returns a procedure LAMBDA N which returns a list with the outgoing edges of node N
- in-edges
- returns a procedure LAMBDA N which returns a list with the incoming edges of node N
- has-edge
- returns a procedure LAMBDA I J which returns true if edge I -> J exists in the graph and false otherwise
- has-node
- returns a procedure LAMBDA N which returns true if node N exists in the graph and false otherwise
- node-info
- returns a procedure LAMBDA N which returns the metadata for node N
- node-info-set!
- returns a procedure LAMBDA N V which sets the metadata for node N
- foreach-node
- returns an iterator procedure LAMBDA F which iterates over the nodes in the graph by invoking function F on the node number and metadata of each node
- foreach-edge
- returns an iterator procedure LAMBDA F which iterates over the edges in the graph by invoking function F on each edge
Examples
;; example adapted from graph example in the Boost library documentation (import srfi-1 digraph matchable) (define g (make-digraph 'depgraph "dependency graph")) (define used-by (list (cons 'dax_h 'foo_cpp) (cons 'dax_h 'bar_cpp) (cons 'dax_h 'yow_h) (cons 'yow_h 'bar_cpp) (cons 'yow_h 'zag_cpp) (cons 'boz_h 'bar_cpp) (cons 'boz_h 'zig_cpp) (cons 'boz_h 'zag_cpp) (cons 'zow_h 'foo_cpp) (cons 'foo_cpp 'foo_o) (cons 'foo_o 'libfoobar_a) (cons 'bar_cpp 'bar_o) (cons 'bar_o 'libfoobar_a) (cons 'libfoobar_a 'libzigzag_a) (cons 'zig_cpp 'zig_o) (cons 'zig_o 'libzigzag_a) (cons 'zag_cpp 'zag_o) (cons 'zag_o 'libzigzag_a) (cons 'libzigzag_a 'killerapp))) (define node-list (delete-duplicates (concatenate (list (map car used-by) (map cdr used-by))))) (define node-ids (list-tabulate (length node-list) values)) (for-each (lambda (i n) (add-node! g i n)) node-ids node-list) (define node-map (zip node-list node-ids)) (for-each (lambda (e) (match e ((ni . nj) (let ((i (car (alist-ref ni node-map))) (j (car (alist-ref nj node-map)))) (add-edge! g (list i j (format "~A->~A" ni nj))))) (else (error "invalid edge " e)))) used-by) (print (nodes g)) (print (edges g)) (remove-node! g 0) (print (nodes g)) (print (edges g))
About this egg
Author
Version history
- 2.0
- Ported to CHICKEN 5 and yasos
- 1.16
- Added terminals message to digraph object
- 1.15
- Ensure unit test script return proper exit code
- 1.13
- Added test as a test dependency
- 1.12
- Converted documentation to wiki format
- 1.11
- Ported to Chicken 4
- 1.10
- Now using matchable extension
- 1.9
- Added procedures pred-list and succ-list
- 1.8
- Added procedure node-info-set!
- 1.7
- Build script updated for better cross-platform compatibility
- 1.6
- Test infrastructure changed to use testbase
- 1.5
- Bug fixes in set-out-edges! and set-in-edges! [thanks to Andreas Scholta]
- 1.4
- License upgrade to GPL v3
- 1.3
- Updated the roots procedure to match the documentation
- 1.2
- Minor changes to the setup script
- 1.1
- Added support for chicken-setup -test
- 1.0
- Initial release
License
Copyright 2007-2018 Ivan Raikov. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. A full copy of the GPL license can be found at <http://www.gnu.org/licenses/>.